1. Field of the Invention
This invention relates generally to vehicle auxiliary electrical equipment and fuse panels and more particularly to a D.C. power distribution and fuse panel unit for connecting a plurality of vehicle auxiliary electrical devices which is controlled by the vehicle ignition and has constant power, ignition controlled, and delayed power shut-off circuits for the various devices.
2. Brief Description of the Prior Art
The installation and trouble shooting of vehicle auxiliary electrical equipment such as two-way radios, sirens, computers, and mobile phones in police and other emergency vehicles has heretofore been a time consuming and expensive process. Several variations of installation methods have existed through the years, each tailored to the requirements of the auxiliary equipment and the needs of the particular organization using the vehicles.
Some organizations wire the auxiliary electrical equipment through ignition operated relays so that the equipment is automatically turned off when the vehicle ignition is turned off.
Other organizations use relays with timers to achieve a delayed shut-off required by a computer mobile data terminal (MDT) to prevent a slow down or total shut down of its host computer when it cannot deliver messages back to the MDT because it has been turned off.
Still other organizations simply wire the auxiliary electrical equipment hot (connected direct to the battery) and depend on the operator to physically turn off each piece of equipment separately.
All of the installation methods described above have certain drawbacks and limitations. The ignition controlled relay installation requires the vehicle ignition switch to be turned on (keys in the vehicle) to operate the equipment. Wiring the auxiliary electrical equipment hot causes dead batteries when the operator forgets to turn the equipment off. The delayed shut-off relay and timer combination keeps all equipment active during the shut-off delay.
Regardless of the installation method used, each piece of auxiliary electrical equipment still requires one or more power leads that usually have an in-line fuse holder spliced into the wire. When relays are used, they must be mounted and wired into the system. This is usually accomplished under the hood of the vehicle, and each wire must be passed through the firewall of the vehicle to reach the auxiliary equipment. In the case of a police vehicle emergency light bar, it may have as many as eight leads and each circuit in the light bar requires an in-line fuse to protect the light controller.
Thus, installation of vehicle auxiliary electrical equipment such as two-way radios, sirens, computers, and mobile phones in police and other emergency vehicles is a labor intensive time consuming process and the resultant large bundle of wires makes trouble shooting a simple blown fuse a major ordeal. The task of replacing a blown fuse usually requires unbundling the numerous wires so that a wire could be traced to the proper in-line fuse holder and then rebundling the numerous wires after the blown fuse is replaced.
There are several patents which disclose systems for controlling auxiliary power devices in a vehicle.
Anki et al, U.S. Pat. No. 4,403,155 discloses an improved wiring system in which a connection box having a plurality of terminals, electrical circuitry, and bus bars. Each bus bar provides a forked conductive path between the circuitry and terminals and allows outside connectors to be connected by wires in a one-to-one correspondence.
Mane et al, U.S. Pat. No. 4,689,718 discloses a programmable automobile junction box housing printed circuit boards having receptacles for receiving tabs depending from an elongated member which connect the circuit pathways corresponding to vehicle options.
Sawai et al, U.S. Pat. No. 4,850,884 discloses a controller with wiring for a vehicle. The controller has a junction block with at least one bus bar circuit board on which harness branch circuits to which electrical devices are connected.
Copeland et al, U.S. Pat. No. 4,864,154 discloses a solid state digital and analog circuit which is connected between the vehicle battery and a two-way radio, public address system, etc. in an emergency vehicle to prevent the auxiliary electrical device from draining the battery. When the ignition is turned off, a timer and relay in the circuit disconnects the auxiliary device after a prescribed amount of time.
Tamer, U.S. Pat. No. 4,956,561 discloses a smart power connector for use in a vehicular smart power multiplexing network Smart power connectors connect the power network with various peripheral devices.
The present invention is distinguished over the prior art in general, and these patents in particular by a D.C. power distribution and fuse panel unit which facilitates installation and trouble shooting of vehicle auxiliary electrical equipment such as two-way radios, sirens, computer mobile data terminals, and mobile phones in police and other emergency vehicles. The unit is installed beneath the dash of a vehicle or other location inside the vehicle and is connected to the battery by a single wire which passes through the firewall, and is joined to the ignition circuit by a second wire connected to a suitable point such as the existing vehicle fuse block. The unit is supplied with a constant source of positive D.C. voltage, and also with ignition voltage when the vehicle ignition switch is turned on. The unit contains solid state circuitry including relay circuits, timer circuit, and has a plurality of fused power output terminals including constant power, ignition controlled power, and delayed power shut-off terminals for connecting various auxiliary electrical devices having different power disconnect requirements, and may also have a plurality of individual fused input/output circuits. The unit provides a common power distribution module for connecting and supplying power to various types of auxiliary electrical equipment according to their particular requirements. The unit may also have a test switch to speed up the delayed shut-off sequence and allow rapid testing and trouble shooting.